An investor group led by Xstrata Copper will conduct a study on the viability of a $5.2 billion copper-gold project in southern Philippines, Reuters quoted Xstrata as saying.

Xstrata Copper, one of the world's top copper miners and a unit of diversified Swiss global miner Xstrata, has a controlling 62.5 percent interest in the Tampakan project, considered the largest undeveloped copper-gold deposit in Southeast Asia.

"The decision to develop a major copper mine at Tampakan will depend on the outcome of the feasibility study, which will examine the economic, social and environmental viability of this project," Peter Forrestal, president of Xstrata Copper's Philippine affiliate Sagittarius Mines Inc said in a statement.

Sagittarius said it has hired engineering firm Bechtel for the $74-million feasibility study. Results of the study are expected to be submitted to the Philippine government by the second quarter of 2010.

A pre-feasibility study released in April showed developing Tampakan would require an initial outlay of $5.2 billion, more than double the previous estimate of around $2 billion.

The mine is estimated to contain 12.8 million tonnes of copper and 15.2 million ounces of gold.

It is projected to produce an average 340,000 tonnes of copper a year and 350,000 ounces of gold for a 20-year operation period, according to Xstrata. First production is targeted in early 2016.

Other project shareholders include Australian miner Indophil Resources with 34.23 percent and Philippine firm Alsons Corp with 3.27 percent.

Discovered in 1991, the project has never left the drawing board due to environmental problems and communist insurgencies.